60 Selected notes to the consolidated income statement. Net revenue. Q1 2011 millions of € Q1 2010 millions of € Change millions of € Change % FY 2010 millions of € Net revenue 10,830 12,002 (1,172) (9.8) 46,346 For details of changes in net revenue, please refer to the section “Development of business in the Group” in the interim Group management report. Cost of sales. Q1 2011 millions of € Q1 2010 millions of € Change millions of € Change % FY 2010 millions of € Cost of sales (6,282) (7,035) 753 10.7 (27,052) Cost of sales decreased by EUR 0.8 billion compared with the first quarter of 2010. This development was the result of the consolidation effect of EUR 0.4 billion described in the section “Changes in the composition of the Group.” In addition, a write-off of receivables from the German main customs office for the years 2005 to 2009 was included in cost of sales in the prior-year quarter. Selling expenses. Q1 2011 millions of € Q1 2010 millions of € Change millions of € Change % FY 2010 millions of € Selling expenses (2,351) (2,533) 182 7.2 (9,873) The main reason for the decrease of EUR 0.2 billion in selling expenses was the previously described effect of changes in the composition of the Group.